阅读说明：本技术 用于机动车辆的动力转向系统的辅助模块 (Auxiliary module for a power steering system of a motor vehicle ) 是由 米克·盖琳 于 2020-08-18 设计创作，主要内容包括：一种用于机动车辆的动力转向系统的辅助模块,包括减速器壳体(3),其中的减速器连结至设置有小齿轮(24)的输出轴(2),输出轴(2)通过机械滚动轴承(6)安装在减速器壳体(3)内部,机械滚动轴承承载在相切轮(23)与小齿轮(24)之间,机械滚动轴承(6)具有通过分隔架(65)彼此保持一定距离的多个滚动元件(64),滚动元件和分隔架设置在形成于内环(61)与外环(62)之间的环形滚动轴承空间(63)中,该辅助模块的特征在于,其包括具有至少一个止挡表面(33)的至少一个阻挡元件(32),所述止挡表面面向环形滚动轴承空间(63)位于一定距离处,使得止挡表面(33)中的至少一个防止分隔架(65)从环形滚动轴承空间(63)中弹出。(An auxiliary module for a power steering system of a motor vehicle, comprising a reducer housing (3) in which the reducer is linked to an output shaft (2) provided with a pinion (24), the output shaft (2) being mounted inside the reducer housing (3) by means of a mechanical rolling bearing (6) carried between a tangent wheel (23) and the pinion (24), the mechanical rolling bearing (6) having a plurality of rolling elements (64) held at a distance from each other by a spacer (65), the rolling elements and the spacer being arranged in an annular rolling bearing space (63) formed between an inner ring (61) and an outer ring (62), the auxiliary module being characterized in that it comprises at least one blocking element (32) having at least one stop surface (33) located at a distance facing the annular rolling bearing space (63), so that at least one of the stop surfaces (33) prevents the spacer (65) from popping out of the annular rolling bearing space (63).)

1. An assistance module for a power steering system (1) of a motor vehicle, comprising a reducer housing (3) in which a reducer is mounted, said reducer comprising an output shaft (2) provided with a pinion (24), said output shaft (2) being rotatably mounted inside said reducer housing (3) around a longitudinal axis (22) by means of at least one mechanical rolling bearing (6) carried between a tangent wheel (23) and said pinion (24) by a bearing (31) provided on said reducer housing (3),

the mechanical rolling bearing (6) has a plurality of rolling elements (64) held at a distance from each other by a spacer (65), the rolling elements and the spacer (65) being arranged in an annular rolling bearing space (63) formed between an inner ring (61) and an outer ring (62) which are coaxial,

the spacer can be ejected from the annular rolling bearing space (63) in an ejection direction (654),

the auxiliary module is characterized in that it comprises at least one blocking element (32; 7; 8; 9; 11; 12; 14; 15; 16; 17; 18) having at least one stop surface (33; 71; 81; 91; 111; 121; 141; 151; 161; 171; 181) which faces the annular rolling bearing space (63) and is located at a distance in an ejection direction (654) such that at least one of the stop surfaces (33; 71; 81; 91; 111; 121; 141; 151; 161; 171; 181) prevents the spacer (65) from being ejected from the annular rolling bearing space (63).

2. Auxiliary module according to the preceding claim, wherein the rolling elements are spherically shaped balls (64) and wherein the distance is less than or equal to half the diameter of the balls.

3. Auxiliary module according to the previous claim, wherein said distance is less than or equal to 2 mm.

4. Auxiliary module according to the preceding claim, wherein at least one stop surface (33; 71; 81; 91; 111; 181) is positioned along the longitudinal axis (22) between the mechanical rolling bearing (6) and the tangent wheel (23).

5. Auxiliary module according to any of the preceding claims, wherein at least one stop surface (121; 141; 151; 161; 171) is positioned along the longitudinal axis (22) between the mechanical rolling bearing (6) and the pinion (24).

6. Auxiliary module according to any of the preceding claims, wherein at least one blocking element (32; 7) is fixed to the retarder housing (3).

7. Auxiliary module according to the preceding claim, wherein the blocking element (32) is made integrally with the retarder housing (3).

8. Auxiliary module according to the preceding claim, wherein the blocking element (32) is produced together with the retarder housing (3) by a casting method.

9. Auxiliary module according to claim 4, wherein the blocking element (7) is fixed to the retarder housing (3) by screwing, welding or press-fitting.

10. Auxiliary module according to any of the preceding claims, wherein at least one blocking element (8) is interposed between a shoulder (34) of the reducer housing (3) and an outer ring (62) of the mechanical rolling bearing (6).

11. Auxiliary module according to any of the preceding claims, wherein at least one blocking element (9; 18) is fixed to the output shaft (2).

12. Auxiliary module according to the preceding claim, wherein the blocking element (9) is made integrally with the output shaft (2).

13. Auxiliary module according to claim 11, wherein the blocking element (18) is fixed to the output shaft (2) by screwing, welding or press-fitting.

14. Auxiliary module according to any of the preceding claims, wherein at least one blocking element (11) is interposed between a shoulder (25) of the output shaft (2) and the inner ring (61).

15. Auxiliary module according to any one of the preceding claims, wherein a blocking element (12; 14) is affixed to a clamping nut (10) and abuts against the outer ring (62), the clamping nut (10) being screwed inside the bearing (31) between the mechanical rolling bearing (6) and the pinion (24).

16. Auxiliary module according to the preceding claim, wherein the blocking element (12) is made integrally with the clamping nut (10).

17. Auxiliary module according to claim 15, wherein the blocking element is fixed to the clamping nut (10) by screwing, welding or press-fitting.

18. Auxiliary module according to any of the preceding claims, wherein at least one blocking element (15) is interposed between the clamping nut (10) and the outer ring (62).

19. Auxiliary module according to any of the preceding claims, wherein a blocking element (16) is affixed to a crimp ring (13) and abuts against the inner ring (61), the crimp ring (13) being crimped inside the bearing (31) between the mechanical rolling bearing (6) and the pinion (24).

20. Auxiliary module according to the preceding claim, wherein the blocking element (16) is made integrally with the crimp ring (13).

21. Auxiliary module according to any of the preceding claims, wherein at least one blocking element (17) is interposed between the crimp ring (13) and the inner ring (61).

22. Auxiliary module according to any of the preceding claims, wherein at least one blocking element (32; 7; 8; 9; 11; 12; 14; 15; 16; 17; 18) has a stop surface (33; 71; 81; 91; 111; 121; 141; 151; 161; 171; 181) of annular shape centred on the longitudinal axis (22).

23. Auxiliary module according to any of the preceding claims 1 to 12, wherein at least one blocking element (32; 7; 8; 9; 11; 12; 14; 15; 16; 17; 18) has a plurality of different stop surfaces (33; 71; 81; 91; 111; 121; 141; 151; 161; 171; 181), the stop surfaces (33; 71; 81; 91; 111; 121; 141; 151; 161; 171; 181) being arranged around the longitudinal axis (22).

Technical Field

The invention relates to an auxiliary module for a power steering system of a motor vehicle.

Background

In a conventional manner, the motor vehicle may be provided with a power steering system, so that the effort provided by the driver of the motor vehicle for guiding the motor vehicle may be reduced.

Such power steering systems generally comprise a steering module comprising a steering rack, the ends of which are associated with the steered wheels of the motor vehicle by means of tie rods, and an auxiliary module comprising an auxiliary motor which rotationally drives an output shaft provided with a pinion engaging with the steering rack of the steering module: it is thus possible to transmit an assistance torque to the steering rack which is added to the torque provided by the driver of the motor vehicle on the steered wheels of the motor vehicle, thus facilitating the driving thereof.

More specifically, the auxiliary motor drives a worm engaged in a reducer housing on a tangent wheel rotationally connected to an output shaft rotatably mounted inside the reducer housing by means of at least one mechanical rolling bearing carried between the tangent wheel and a pinion by a bearing provided on the reducer housing.

Such mechanical rolling bearings generally comprise a plurality of rolling elements held at a distance from one another by a spacer made of plastic material clamped on the rolling elements, these rolling elements and this spacer being arranged in an annular rolling bearing space formed between an inner ring and a coaxial outer ring.

However, in the presence of high mechanical stresses on the mechanical rolling bearing, for example during significant misalignment of the output shaft with respect to the reducer housing, the spacer can at least partially pop out of the annular rolling bearing space.

Such an ejection of the spacer can then lead to a recombination of the individual rolling elements of the mechanical rolling bearing in the annular rolling bearing space and then to a drastic reduction, or even a complete loss, of the rotational guidance of the output shaft relative to the gear housing.

In order to solve this problem, it is known to add a flange provided between the inner ring and the outer ring on the mechanical rolling bearing so that the pop-up of the spacer can be physically prevented.

For example, the flange may be fixed by clamping on the outer or inner ring of the mechanical rolling bearing, but this solution requires the formation of a clamping groove on one of the latter.

Therefore, the addition of such flanges on mechanical rolling bearings involves modifying and making more complex the structure thereof and therefore represents a significant economic cost.

Another solution is to use larger mechanical rolling bearings, which can withstand greater loads and misalignment of the output shaft, but this also results in additional economic costs.

Disclosure of Invention

The present invention proposes to solve some or all of the above drawbacks by proposing a solution that makes it possible to keep the spacer of the mechanical rolling bearing in the annular rolling bearing space without modifying the structure of the mechanical rolling bearing.

Another object of the invention is to propose an inexpensive solution.

To this end, the invention provides an auxiliary module for a power steering system of a motor vehicle, comprising a reducer housing in which is mounted a reducer, for example a gear reducer, rotationally coupled to an output shaft provided with a pinion, comprising a worm driven by an auxiliary motor and meshing on a tangent wheel rotationally coupled to the output shaft, said output shaft being rotatably mounted inside the reducer housing around a longitudinal axis by means of at least one mechanical rolling bearing carried between the tangent wheel and the pinion by a bearing provided on the reducer housing,

the mechanical rolling bearing has a plurality of rolling elements which are held at a distance from one another by a spacer, the rolling elements and the spacer being arranged in an annular rolling bearing space formed between an inner ring and a coaxial outer ring,

the spacer can be ejected from the annular rolling bearing space in an ejection direction,

the auxiliary module is characterized in that it comprises at least one blocking element having at least one stop surface which faces the annular rolling bearing space and is located at a distance in the ejection direction such that at least one of the stop surfaces prevents ejection of the spacer from the annular rolling bearing space.

In the presence of significant mechanical stresses on the mechanical rolling bearing, the spacer thus undergoes possible deformations, but does not spring out of the annular rolling bearing space, since the movement of the spacer in the spring-out direction (parallel to the longitudinal axis) is limited by at least one stop surface arranged opposite the annular rolling bearing space.

Due to the special shape present in the gear housing, in the form of the blocking element whose stop surface(s) limit the movement of the mechanical rolling bearing spacer, it is possible to prevent (completely or partially) the spacer from popping out of the annular rolling bearing space.

The spacer can therefore continue to perform its function of keeping the rolling elements of the mechanical rolling bearing at a distance from one another even in the presence of strong mechanical stresses on the mechanical rolling bearing.

It should be noted that the auxiliary module according to the invention may thus comprise one or more blocking elements, each having one or more stop surfaces preventing the spacers from springing out in various directions.

According to one possibility, the rolling elements are spherical balls and said distance is less than or equal to half the diameter of these balls.

According to another possibility, said distance is less than or equal to 2 mm.

Thus, the stop surfaces are positioned close enough to the inner and outer rings of the mechanical rolling bearing that the spacer cannot be ejected from the annular rolling bearing space between them.

In one embodiment, the at least one stop surface is positioned along the longitudinal axis between the mechanical rolling bearing and the tangent wheel.

This positioning of the stop surfaces thus makes it possible to prevent the spacers from springing out in the direction of the tangent wheels.

According to one possibility, at least one stop surface is positioned along the longitudinal axis between the mechanical rolling bearing and the pinion.

This positioning of the stop surface makes it possible to prevent the spacer from springing out in the direction of the pinion (that is to say in the direction opposite to the tangent wheel).

It should be noted that in practice it is only necessary to provide at least one stop surface "on one side" of the mechanical rolling bearing along the longitudinal axis, that is to say to provide the stop surface(s) either between the mechanical rolling bearing and the pinion or between the mechanical rolling bearing and the tangent wheel.

In fact, during the installation of the mechanical rolling bearing, the spacer is generally clamped on the rolling elements and positioned inside the annular rolling bearing space, either between the rolling elements and the pinion, or between the rolling elements and the tangent wheel: the spacer can thus be ejected from the annular roller bearing space only in one ejection direction, which is oriented either toward the tangent wheel or toward the pinion.

The direction of ejection of the spacer is thus oriented either towards the tangent wheel or towards the pinion, depending on the direction of installation of the mechanical rolling bearing in the steering housing.

Thus, a single stop surface, arranged facing the annular rolling bearing space and on the "right" side of the mechanical rolling bearing (that is to say either between the mechanical rolling bearing and the pinion or between the mechanical rolling bearing and the tangent wheel, depending on the orientation of the ejection direction), may be sufficient to prevent ejection of the spacer.

It is also conceivable to provide at least one stop surface on "each side" of the mechanical rolling bearing along the longitudinal axis, that is to say between the mechanical rolling bearing and the pinion and between the mechanical rolling bearing and the tangent wheel.

In this way, it is not necessary to know the orientation of the ejection direction of the rolling-contact bearing cartridge.

According to one possibility, the blocking element is integrated with the retarder housing.

It is therefore necessary to provide the blocking element in such a way that the stop surface is positioned facing the annular rolling bearing space once the output shaft and the mechanical rolling bearing are mounted in the reducer housing.

According to one possibility, the blocking element is made integrally with the gear housing.

According to another possibility, the blocking element is produced together with the retarder housing by means of a casting method.

The production of the blocking element by means of a casting method therefore makes it possible to integrate the blocking element into the gear housing in an inexpensive manner.

According to yet another possibility, the blocking element is fixed to the reducer housing by screwing, welding or press-fitting.

In one embodiment, at least one blocking element is interposed between a shoulder of the reducer housing and the outer ring of the mechanical rolling bearing.

For example, the blocking element may take the form of a washer which abuts against the outer ring and extends partially opposite the annular rolling bearing space.

In a variant, at least one blocking element is fixed to the output shaft.

According to one possibility, the blocking element is made integral with the output shaft.

According to one possibility, the blocking element is made integrally with the output shaft.

According to one feature, the blocking element is fixed to the output shaft by screwing, welding or press fitting.

According to another possibility, at least one blocking element is inserted between the shoulder of the output shaft and the inner ring.

For example, the blocking element may take the form of a washer which abuts against the inner ring and extends partly towards the annular rolling bearing space.

In one embodiment, the blocking element is fixed to a clamping nut screwed inside the bearing between the mechanical rolling bearing and the pinion and abuts against the outer ring.

The main function of this clamping nut is to block the mechanical rolling bearing in the bearing of the reducer housing: the structure may be modified so as to add to the clamping nut a stop surface facing the annular rolling bearing space.

According to one feature, the blocking element is made in one piece with the clamping nut.

According to another feature, the blocking element is fixed to the clamping nut by screwing, welding or press-fitting.

According to one possibility, at least one blocking element is inserted between the clamping nut and the outer ring.

In a variant, the blocking element is fixed to a crimping ring crimped between the mechanical rolling bearing and the pinion inside the bearing and abuts against the inner ring.

In the same way as the clamping nut, this crimping ring has the function of blocking the mechanical rolling bearing in the bearing of the reducer housing: it is also possible to modify the structure thereof so as to add a stop surface facing the annular rolling bearing space to the crimp ring.

According to one feature, the blocking element is made integrally with the crimp ring.

According to another feature, the blocking element is fixed to the crimp ring by screwing, welding or press-fitting.

According to one possibility, at least one blocking element is inserted between the crimping ring and the inner ring.

For example, the blocking element may thus take the form of a washer which abuts against the crimp ring or the clamping nut and extends partly towards the annular rolling bearing space.

In one embodiment, the at least one blocking element has an annular stop surface centered on the longitudinal axis.

According to one possibility, at least one blocking element has a plurality of different stop surfaces, which are arranged around the longitudinal axis.

The invention thus enables a wide variety of embodiments as regards the nature of the at least one blocking element and its positioning with respect to the mechanical rolling bearing.

In particular, the blocking element(s) may:

-between a mechanical rolling bearing and a pinion, or between a mechanical rolling bearing and a tangent wheel;

-a fastening to the steering housing, the output shaft, the clamping nut or the crimp ring; or

Is constituted by an additional element (for example of the washer type) interposed between the mechanical rolling bearing and the steering housing, the output shaft, the clamping nut or the crimp ring;

-having a single annular stop surface or a plurality of different stop surfaces arranged around the longitudinal axis.

Depending on the specific application, these embodiments can also be combined with each other in order to better ensure that the spacer cannot be ejected.

Drawings

Further characteristics and advantages of the invention will appear on reading the following detailed description of an example of a non-limiting embodiment thereof, with reference to the attached drawings, in which:

FIG. 1 is a cross-sectional view of a prior art power steering system;

figure 2 is an exploded view of a mechanical rolling bearing comprising a spacer;

FIG. 3 is a cross-sectional view of a first embodiment of an auxiliary module according to the present invention;

FIG. 4 is a cross-sectional view of a second embodiment of an auxiliary module according to the present invention;

FIG. 5 is a cross-sectional view of a third embodiment of an auxiliary module according to the present invention;

FIG. 6 is a cross-sectional view of a fourth embodiment of an auxiliary module according to the present invention;

fig. 7 is a cross-sectional view of a fifth embodiment of an auxiliary module according to the invention;

fig. 8 is a cross-sectional view of a sixth embodiment of an auxiliary module according to the invention;

FIG. 9 is a cross-sectional view of a seventh embodiment of an auxiliary module according to the present invention;

fig. 10 is a cross-sectional view of an eighth embodiment of an auxiliary module according to the invention;

fig. 11 is a cross-sectional view of a ninth embodiment of an auxiliary module according to the invention;

fig. 12 is a cross-sectional view of a tenth embodiment of an auxiliary module according to the present invention;

fig. 13 is a cross-sectional view of an eleventh embodiment of an auxiliary module according to the present invention;

fig. 14 is a perspective view (fig. 14a) and a front view (fig. 14b) of a first embodiment of an auxiliary module according to the invention;

fig. 15 is a perspective view (fig. 15a) and a front view (fig. 15b) of a first embodiment of an auxiliary module according to the invention.

Detailed Description

Fig. 1 shows a prior art power steering system 1 for a motor vehicle.

The power steering system 1 comprises in particular an output shaft 2 which is mounted for rotatable movement about a longitudinal axis 22 in a gearbox housing 3.

The output shaft 2 is fixed to a tangent wheel 23 meshing with a worm 4, the worm 4 itself being driven in rotation by an auxiliary motor (not shown).

The output shaft 2 also has a pinion 24 which meshes with a rack 5 provided in a steering housing 51: the rotational movement of the output shaft 2 about the longitudinal axis 22 thus results in a translational movement of the rack 5 in a direction orthogonal to the longitudinal axis 22.

The power steering system 1 can thus transmit the motor torque transmitted to the worm 4 through the assist motor (not shown) to the rack 5 so as to assist the driver of the electric vehicle in steering the electric vehicle.

Specifically, the output shaft 2 is mounted on the reduction gear case 3 via a mechanical rolling bearing 6 provided in a bearing portion 31 of the reduction gear case 3.

In this embodiment, the mechanical rolling bearing 6 is formed by an inner ring 61 and an outer ring 62 which are coaxial and centered on the longitudinal axis 22.

The space between the inner ring 61 and the outer ring 62 constitutes an annular moving space 63 in which rolling balls 64 are disposed.

These rolling balls 64 are held at a distance from one another by a spacer 65 which is likewise arranged in the annular rolling bearing space 63 of the mechanical rolling bearing 6.

The mechanical rolling bearing 6 thus enables a rotational movement of the output shaft 2 relative to the gear housing 3 about the longitudinal axis 22.

In such a power steering system 1 of the related art, it is possible to: after significant mechanical stress is exerted on the mechanical rolling bearing 6 (e.g. after misalignment of the output shaft 2 with respect to the longitudinal axis 22), the spacer 65 undergoes significant deformation and is ejected from the annular rolling bearing space 63 in an ejection direction that is collinear with the longitudinal axis 22.

Fig. 2 shows the mechanical rolling bearing 6 in an exploded view, comprising rolling balls 64 arranged between the inner ring 61 and the outer ring 62.

The mechanical rolling bearing 6 also comprises a protection 68.

The beads 64 are held at a distance from each other by a spacer 65.

The spacer 65 has a front face 651 and an opposite rear face 652, and comprises receptacles 653 formed in the front face 651, each of these receptacles 651 having a shape suitable for receiving a ball 64: the spacer thus "grips" (that is, is held in place by pressure) the ball 64 by its front face.

Due to its particular construction, the receptacle 653 has an opening that is open only at the front face 651, and the spacer 65 can only be separated from the ball 64 by movement in the ejection direction 654.

The orientation of this ejection direction 654 therefore depends on the mounting direction of the spacer 65 in the mechanical rolling bearing 6.

Once the mechanical rolling bearing 6 is positioned in the bearing portion 31 of the steering housing 51, this ejection direction 654 is collinear with the longitudinal axis 22 and defines an ejection trajectory of the spacer 65 outside the annular rolling bearing space 63: depending on the installation direction of the spacer in the mechanical rolling bearing 6, it can spring out either in the direction of the tangent wheel 23 or in the direction of the pinion 24.

Therefore, knowing the orientation of this ejection direction 654, it is necessary to provide a blocking element along the longitudinal axis 22 only on one side of the mechanical rolling bearing 6, that is to say either between the mechanical rolling bearing 6 and the pinion 24 or between the mechanical rolling bearing 6 and the tangent wheel 23.

Embodiments comprising a plurality of blocking elements arranged between the mechanical rolling bearing 6 and the pinion 24 and between the mechanical rolling bearing 6 and the tangent wheel 23 are also conceivable.

Fig. 3a shows the power steering system 1 according to the invention, and fig. 3b is a detailed view of the support portion 31.

In this embodiment shown in fig. 3, the spacer 65 is capable of ejecting in an ejection direction 654 in the direction of the tangent wheel 23.

The reducer housing 3 comprises a blocking element 32 arranged between the tangent wheel 23 and the bearing 31, which blocking element 32 has a stop surface 33 extending facing the annular rolling bearing space 63 of the mechanical rolling bearing 6.

In particular, the stop surface 33 is positioned perpendicularly to the ejection axis 66, which represents the trajectory of the spacer 65 in the ejection direction 654.

The stop surface 33 intersects the ejection axis 66 in the vicinity of the ball rolling bearing 6: in this way, the stop surface 33 physically prevents the movement of the spacer 65 along the ejection axis 66 and in the direction of the tangent wheel 23.

The blocking element 32 can thus prevent (at least partially) the spacer 65 from popping out of the annular rolling bearing space 63 in the direction of the tangent wheel 23.

In this embodiment, the blocking element is made in one piece with the gear housing 3 and is produced together with this gear housing 3 by means of a casting method.

Obviously, many other embodiments of the invention are conceivable, in particular as regards the shape of the blocking element 32 and its stop surface 33, and their placement with respect to the mechanical rolling bearing 6 and with respect to the annular rolling bearing space 63.

Fig. 4 shows an alternative embodiment of the invention, in which the blocking element 7 on the outside of the gear housing 3 is fastened to the gear housing by screwing or welding or even by press fitting.

The blocking element 7 has a stop surface 71 which is arranged perpendicularly to the ejection axis 66 and faces the annular rolling bearing space 63 of the mechanical rolling bearing 6.

In this way, the blocking element 7 can prevent the spacer 65 from being ejected from the annular rolling bearing space 63 along the ejection axis 66 and in the direction of the tangent wheel 23.

Fig. 5 shows a third embodiment of the invention, in which the blocking element is formed by a washer 8 inserted between the outer ring 62 of the mechanical rolling bearing 6 and the shoulder 34 of the reducer housing 3.

The washer 8 is therefore positioned between the mechanical rolling bearing 6 and the tangent wheel 23 abutting against the outer ring 62 and has a stop surface 81 extending perpendicularly to the ejection axis 66 facing the annular rolling bearing space 63.

As previously mentioned, the presence of this washer 8 thus makes it possible to physically prevent the spacer 65 from popping out of the annular rolling bearing space 63 in the direction of the tangent wheel 23.

For example, it is conceivable for the gasket 8 to be made of a metal or plastic type material.

It should be noted that it is possible to combine the various embodiments described previously, for example by associating the use of the washer 8 (external to the reducer casing 3) shown in fig. 5 with the use of the blocking element 32 (solidly connected to the reducer casing 3) shown in fig. 3, this blocking element 32 being made integral with the shoulder 34.

Fig. 6 to 8 below represent a fourth, fifth and sixth embodiment of the invention, respectively, in which the blocking element is fixed to the output shaft 2 and, as previously mentioned, is adapted to prevent the spacer 65 from springing out in the direction of the tangent wheel 23.

Specifically, in the fourth embodiment of the invention depicted in fig. 6, the power steering system 1 has the blocking element 9 integrally formed with the output shaft 2.

The blocking element 9 has a stop surface 91 which extends facing the annular rolling bearing space 63 and perpendicularly intersects the ejection axis 66: the blocking element 9 can thus in this way prevent an ejection movement of the spacer 65 from the annular rolling space 63 along the ejection axis 66 and in the direction of the tangent wheel 23.

It should be noted that the blocking element 9 is solidly connected to the output shaft 2, which is also driven in its rotary movement about the longitudinal axis 22.

Similarly, in the fifth embodiment depicted in fig. 7, the blocking element 9 made integral with the output shaft 2 is replaced by a blocking element 18 external to the output shaft 2 and fixed thereto by screwing, welding or press-fitting.

The blocking element 18 has a stop surface 181 which intersects the ejection axis 66 and thus prevents the spacer 65 from being ejected from the annular rolling bearing space 63 in the direction of the tangent wheel 23.

Fig. 8 shows a sixth embodiment of the invention, in which the blocking element takes the form of a washer 11 positioned between the shoulder 25 of the output shaft 2 and the inner ring 61 of the mechanical rolling bearing 6 and has a stop surface 111 opposite the annular rolling bearing space 63 and extending perpendicularly to the ejection axis 66.

The washer 11 can thus in this way prevent an ejection movement of the spacer 65 from the annular rolling bearing space 63 along the ejection axis 66 and in the direction of the tangent wheel 23.

Fig. 9 to 13 below show embodiments of the invention in which suitable blocking elements can prevent the spacer 65 from popping out of the annular rolling bearing space 63 in the direction of the pinion 24, that is to say in the opposite pop-out direction to that of the embodiment previously described by fig. 1 to 7.

In particular, the following fig. 9, 10 and 11 represent a seventh, eighth and ninth embodiment of the invention, respectively, in which the blocking element is secured to the clamping nut 10, while the following fig. 12 and 13 represent a tenth and eleventh embodiment of the invention, respectively, in which the blocking element is secured to the crimp ring 13.

With reference to fig. 9, the steering system 1 comprises a blocking element 12 made in one piece with a clamping nut 10 screwed inside a bearing 31 of the reducer casing 3 between the mechanical rolling bearing 6 and the pinion 24, abutting against the same mechanical rolling bearing 6.

The function of this clamping nut 10 is to hold the mechanical rolling bearing 6 in place in the bearing 31 of the reducer housing 3.

In the embodiment shown in fig. 9, the blocking element 12, which is formed integrally with the clamping nut 10, has a stop surface 121 which extends perpendicularly to the ejection axis 66, facing the annular rolling bearing space 63.

Thus, the stop surface 121 can physically prevent the ejecting movement of the spacer 65 from the annular rolling bearing space 63 in the direction of the pinion 24.

Similarly, in the embodiment depicted in fig. 10, the blocking element 12 made integral with the clamping nut 10 is replaced by a blocking element 14 which is external to the clamping nut 10 and is fixed to the clamping nut by screwing, welding or press-fitting.

The blocking element 14 has a stop surface 141 which intersects the ejection axis 66 and thus prevents the spacer 65 from being ejected from the annular rolling bearing space 63 in the direction of the pinion 24.

In the embodiment shown in fig. 11, the blocking element takes the form of a washer 15 positioned between the clamping nut 10 and the outer ring 62 of the mechanical rolling bearing 6 and has a stop surface 151 extending perpendicularly to the ejection axis 66 facing the annular rolling bearing space 63.

The washer 15 can thus in this way prevent an ejection movement of the spacer 65 from the annular rolling bearing space 63 along the ejection axis 66 and in the direction of the pinion 24.

It will also be noted in these figures 9 to 11 that there is a blocking element 32 fixed to the reducer housing 3, the stop surface 33 of which prevents (as described earlier) the ejection movement of the spacer 65 in the opposite direction (i.e. in the direction of the tangent wheel 23).

Fig. 12 shows a tenth embodiment of the invention, in which the blocking element 16 is made integrally with the crimp ring 13.

This crimping ring 13 has the function of holding the mechanical rolling bearing 6 in position in the bearing 31 of the reducer housing 3 (similar to the clamping nut 10) and is normally positioned between the mechanical rolling bearing 6 and the pinion 24, abutting against the inner ring 61.

The blocking element 16 has a stop surface 161 which intersects the ejection axis 66 and thus prevents the spacer 65 from being ejected from the annular rolling bearing space 63 in the direction of the pinion 24.

Alternatively, in the embodiment shown in fig. 13, the blocking element takes the form of a washer 17 positioned between the crimping ring 13 and the inner ring 61 of the mechanical rolling bearing 6 and has a stop surface 171 opposite the annular rolling bearing space 63 and extending perpendicularly to the ejection axis 66.

The washer 17 can thus in this way prevent an ejection movement of the spacer 65 from the annular rolling bearing space 63 along the ejection axis 66 and in the direction of the pinion 24.

It should be noted that for each of the embodiments described hereinbefore and represented in a transverse view by the preceding figures 2 to 13, it is conceivable for the stop surface of each blocking element considered to have an annular shape centred on the longitudinal axis 22.

For example, fig. 14a and 14b show the embodiment described by the previous fig. 3 in perspective and front views (along the longitudinal axis 22), respectively.

In these figures, the stop surface 33 of the blocking element 32, made integral with the reducer housing 3, has an annular shape "surrounding" the output shaft 22 and centered on the longitudinal axis 22: this stop surface 33 thus extends over the entire circumference of the outer ring 62 and thus prevents any ejection movement of the spacer 65 from the annular rolling bearing space 63 of the mechanical rolling bearing 6 in the direction of the tangent wheel 23 along any ejection axis parallel to the rotation axis 22 and facing the annular rolling bearing space 63.

On the contrary, it is also conceivable that the blocking elements considered in each of the previous embodiments of fig. 2 to 13 have a plurality of different stop surfaces, which are arranged around the longitudinal axis 22.

For example, fig. 15a and 15b show the embodiment described by the previous fig. 3 in a perspective view and in a front view (along the longitudinal axis 22), respectively.

In this fig. 15, the blocking element 32 (which is fixedly connected to the retarder housing 3) has four stop surfaces 33 which are arranged around the output shaft 2 and equidistantly from the longitudinal axis 22.

In this configuration, the stop surfaces 33 of the blocking element 32 prevent an ejection movement of the spacer 65 from the annular rolling bearing space 63 along a plurality of ejection axes 66 (each stop surface 33 being disposed facing said ejection axis).

However, the ejecting movement of the spacer 65 along the ejection axis 67 located between the stop surfaces 33 (and therefore not facing either of them) is free.

However, due to the rigidity and the dimensions of the spacer 65, it is very unlikely that the spacer will be ejected completely from the annular rolling bearing space 63 of the mechanical rolling bearing 6 in the space separating the two stop surfaces 33: if a portion of a spacer 65 were to be ejected along an ejection axis 67 (not facing the stop surface 33), other adjacent portions of that same spacer 65 would be ejected according to an ejection axis 66 (facing the at least one stop surface 33), then contact will be made with the one or more stop surfaces 33.

Therefore, even if the stopper surface does not extend over the entire periphery of the mechanical rolling bearing 6, the stopper surface 33 can prevent the ejection frame 65 from being ejected integrally from the annular rolling bearing space 63.

The latter solution has the advantage that a good guidance of the output shaft in the gear housing 3 is ensured due to the presence of the blocking element having a smaller area and thus a lower cost stop surface.